Method for eliminating the explosive reaction in a thermit process



nited States Patent METHOD FOR ELIMINATING THE EXPLOSIVE REACTION IN A THERNHT PROCESS Application January 30, 1953, Serial No. 334,348

1 Claim. (Cl. 75-27) N 0 Drawing.

Our invention relates to the method of preventing the explosive action of aluminum or magnesium when heated or burned, and to a new product which will not explode when heated or burned.

Heretofore, the application of heat to aluminum and magnesium in powder, sheet or grains resulted in an explosive action. Therefore, certain chemical processes could not properly be performed.

For example, in the thermit process, that is to say the deoxidation of metal oxides by burning or heating, an explosive reaction is caused when the metal oxides are deoxidized. In the case of magnesium, due to the fact that the boiling point of magnesium is low, the use of magnesium in the thermit process results in an imperfect deoxidization since magnesium evaporates before a full and complete deoxidization is attained. The use of magnesium as a deoxidizing agent under these circumstances is unfeasible. Also, if the deoxidized metal is one which becomes easily oxidized when exposed to open air, a process such as the thermit process which must be performed in the open cannot be used to deoxidize these metals since they are subject to rapid oxidization in open air.

It is therefore an object of this invention to eliminate the explosive reaction accompanying deoxidization by burning of aluminum and magnesium in the form of powder, grains or sheets.

It is a further object of this invention to enable the deoxidization of metal oxides by burning or heating, as in the thermit process to be performed in an enclosed receptacle.

It is a further object of this invention to eliminate the loss of magnesium by evaporation when heated or burned.

It is a further object of this invention to enable burning or heating of aluminum or magnesium by preventing explosive action.

It is a further object of this invention to obtain the use of heat generated by burning or heating of aluminum or magnesium in an open or closed receptacle.

It is a further object of this invention to enable the deoxidization of metal oxide and simultaneously utilize the heat generated by the heating and burning of aluminum or magnesium.

It is a further object of this invention to enable the utilization of light generated when aluminum or magnesium in powder, grain or sheet is burned without explosive action.

7 2,778,723 Patented Jan. 22, 1957 It is a further object of this invention to enable the obtaining of titanium from its oxides by deoxidizing the metal oxides by burning or heating as in the therrnit process in an enclosed receptacle.

It is a further object of this invention to provide for an inexpensive process to attain the other objectives heretofore mentioned.

Other objects and advantages of our invention will be apparent from a study of the following specifications.

When powdered or grain magnesium is employed as a deoxidizing agent, sodium chloride is first mixed with the powdered or grain magnesium. The explosive nature of the magnesium is reduced in proportion to the amount of sodium chloride which is mixed with the magnesium. After an amount of sodium chloride approximately, one and one-third times heavier than the magnesium is mixed with the magnesium, it is possible to eliminate entirely the explosive characteristic of the powdered or grain magnesium and thus obtain a tranquil solid combustion. A greater amount of sodium chloride used will have no adverse elfect.

In the case of aluminum the same result is attained by mixing a larger amount of sodium chloride with the aluminum to eliminate the explosive action entirely of the aluminum, the ratio of sodium chloride to aluminum by weight is approximately 1.85 to. 1.

The prevention of explosive action of aluminum and magnesium in sheets is accomplished by painting one side of the sheet with a suitable amount of sodium chloride which will adhere to the sheet.

In the case of the deoxidization of titanium dioxide by burning the addition of 133% by weight of sodium chloride to the theoretical quantity of magnesium powder required to deoxidize titanium dioxide enables the mixture to be placed into a furnace with titanium dioxide and ignited at temperature of at least 800 centigrade. After the compound is ignited, the compound will quietly burn. The speed with which the compound burns is one cubic decimeter every two minutes. After the deoxidization is completed, the flame will automatically die out. After the reaction is completed, the compound consists of magnesium oxide, amorphous sodium chloride, and titanium.

We claim:

In a thermit process wherein powdered magnesium is used as a deoxidation agent of a metal oxide without explosive reaction, the improvement which consists of first adding and mixing approximately one and one-third portions by weight of sodium chloride to the required quantity of powdered magnesium and then igniting the mixture.

References Cited in the file of this patent UNITED STATES PATENTS 1,140,568 Brown May 25, 1915 2,604,394 Emley July 22, 1952 FOREIGN PATENTS 627,678 Great Britain Aug. 12, 1949 

